[Pellet-users] Pellet does not terminate

[Evren Sirin]

On 4/30/08 6:36 AM, Tobias Kuhn wrote:
> Hi,
>
> As I just found out, it actually terminates but takes about 10 minutes. Sorry, I was not patient enough.
>   

I'm certainly not that patient either :)
> Why does it take so long?
>   

Cardinality restrictions (especially qualified ones) can cause 
combinatorial explosion in some cases. In this specific case, there was 
a problem with a heuristic causing the reasoner to try unnecessary 
things (like deciding which of the planets could also be continents). 
That issue is fixed now and will be included in the upcoming bug-fix 
release but there are other cases where similar things might happen. For 
the record, I created a ticket [1] for this issue and we hope to have a 
more general solution in the future. Example ontologies that use 
qualified cardinality restrictions (or any other new OWL2 feature) in 
interesting ways are appreciated.

Cheers,
Evren

[1] http://cvsdude.com/trac/clark-parsia/pellet-devel/attachment/ticket/121
>
> Tobias
>
>
>
> Tobias Kuhn wrote:
>   
>> Hi,
>>
>> I encountered the problem that Pellet does not terminate for this very small ontology:
>>
>>    http://www.ifi.uzh.ch/cl/tkuhn/superman.owl
>>
>> The content of this ontology can be verbalized as follows:
>>
>>    Superman knows everything.
>>    Superman knows exactly 7 continents.
>>    Superman knows exactly 8 planets.
>>
>> Pellet (1.5.1) does not terminate when trying to process this file via the command-line interface:
>>
>>    bash pellet.sh -if superman.owl
>>
>> Any idea what's going wrong?
>>
>>
>> Tobias
>>     
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